Chat UI Kits + SDK Sample Apps for building in-app mobile chat.
Web App UI kit for Figma
A beautiful Bootstrap 4 UI kit.
1,500 pre-built UI components
Uber Design System
BuzzFeed's CSS style guide
Microsoft's Design System
Polaris Design System by Shopify
IBM's open-source design system
Customizable Design System available for Sketch, with mobile and web implementations
Design system for enterprise-level products
Make better UI with Modular Design System